The present invention relates to a wireless remote control signal transfer method and apparatus and wireless remote control system which transfer a wireless remote control signal, transmitted from an wireless remote control transmitter, to to-be-operated-equipment (hereinafter referred to as “operated equipment”) via a wired transmission path so as to remote-control the operated equipment, and more particularly to a technique for achieving a corresponding function of the operated equipment responsive to so-called “continuous depressing operation” on the remote control transmitter.
Among audio reproduction systems known today are ones of the type where an reproduction apparatus, including for example a CD player, amplifier, etc., is positioned in a single room and speaker cables connected to the reproduction apparatus are laid in a plurality of rooms so that audio signals can be audibly reproduced in the individual rooms. Example of such an audio reproduction system is disclosed in Japanese Patent Application Laid-open Publication No. 2003-45166.
FIG. 2 shows an example general system setup employed for remote-controlling a reproduction apparatus from individual rooms in the aforementioned audio reproduction system. Infrared remote control system 10 of FIG. 2 includes an infrared remote control transmitter 12 and infrared remote control receiver 14 positioned in a room A, and an infrared remote control re-transmitter 16 and operated equipment (i.e., reproduction apparatus) 18 positioned in another room B. The infrared remote control receiver 14 and infrared remote control re-transmitter 16 are connected with each other via a wired transmission path 20. The operated equipment 18 is constructed to operate by directly receiving an infrared remote control signal 22 transmitted from the infrared remote control transmitter 12. In this infrared remote control system 10, however, the operated equipment 18 can not be directly operated or controlled by the infrared remote control transmitter 12 because the infrared remote control transmitter 12 and operated equipment 18 are positioned in the different rooms A and B. Thus, in the system of FIG. 2, the infrared remote control receiver 14 and infrared remote control re-transmitter 16 are provided in the room A and B, respectively, and these receiver 14 and re-transmitter 16 are connected with each other via the wired transmission path 20, comprising an electric cable or optical cable, to thereby constitute an infrared remote control signal transfer apparatus 26. With such an infrared remote control signal transfer apparatus 26, the infrared remote control signal 22 of the infrared remote control transmitter 12 can be transferred to the operated equipment 18 via the infrared remote control signal transfer apparatus 26.
Namely, in the infrared remote control system 10, the infrared remote control transmitter 12 transmits an infrared remote control signal 22 responsive to or corresponding to user's operation of an operation key, such as a push button. The infrared remote control receiver 14 receives the infrared remote control signal 22 from the transmitter 12, analyzes a train of bits of the received control signal 22 and transmits code analysis data (e.g., data obtained by directly converting the bit train into numerical values) 23 to the wired transmission path 20. The infrared remote control re-transmitter 16 receives the code analysis data 23 from the transmission path 20, reproduces an infrared remote control signal 24 (i.e., signal corresponding to the infrared remote control signal 22 transmitted from the infrared remote control transmitter 12) by modulating the bit train, corresponding to the code analysis data 23, with a predetermined carrier wave and then transmits the reproduced infrared remote control signal 24. The operated equipment 18 receives and analyzes the infrared remote control signal 24 and performs a process corresponding to the result of the analysis (i.e., process instructed by the infrared remote control transmitter 12).
Among various operational functions by the conventionally-known infrared remote control transmitters is the so-called “continuous depression function”, which is intended to cause desired operated equipment to perform a special function in response to a user continuously performing one particular operation (i.e., “continuous depressing operation”) on the infrared remote control transmitter. For example, the continuous depression function can be used as a function to gradually increase a volume-up (i.e., volume-increasing) or volume-down (volume-decreasing) speed of an amplifier in accordance with the passage of time, if the user continues to depress a volume-up or volume-down button on the infrared remote control transmitter. The continuous depression function can also be used as a function to gradually increase a fast-forwarding or fast-rewinding speed of an amplifier in accordance with the passage of time, if the user continues to depress a fast-forward or fast-rewind button of a CD player or video player via the infrared remote control transmitter.
If the user continues to depress any one of the buttons of the infrared remote control transmitter in order to perform the continuous depression function, the infrared remote control transmitter repetitively transmits an infrared remote control signal, corresponding to the depressing operation, with a predetermined cyclic frame period as long as the button is depressed. During that time, the operated equipment detects that the infrared remote control signal is repetitively received from the transmitter with the predetermined cyclic period and thereby determines that a continuous depression function is being instructed, so that it performs a predetermined process, preset set as the continuous depression function of the depressed button, as long as the reception of the infrared remote control signal lasts.
The infrared remote control system 10 of FIG. 2 can be constructed in such a manner that transmission of the code analysis data 23 of the infrared remote control signal 22 and other data (e.g., audio signal data) is carried out simultaneously using the wired transmission path 20. In such a case, a plurality of data are subjected to multiplexing (such as time-division multiplexing or frequency multiplexing), and the resultant multiplexed data are transmitted to the wired transmission path 20. Because the transmission of the code analysis data 23 is carried out utilizing an empty time or empty band, it may sometimes become impossible to secure a sufficient speed for transmission of the code analysis data 23.
Let it be assumed here that the infrared remote control signal 22 transmitted from the infrared remote control transmitter 12 has a frame length T0 that is, for example, 108 msec. and that a time T1 is required to transmit, via the wired transmission path 20, the code analysis data 23 of one frame of the infrared remote control signal 22. If the user performs continuous depressing operation on the infrared remote control transmitter 12, the transmitter 12 repetitively transmits, as the infrared remote control signal 22, code data C0, C1, C1, . . . (here, C0 is an operation code and C1 is a repeat code) or code data C0, C0, C0, . . . with a cyclic period equal to the frame length T0. If, during that time, the operated equipment 18 has received the next code (i.e., repeat code C1 or same code as the last operation code C0) within a time period T0+α (α is a leeway time preset in view of possible variation or difference in time management between different operated equipment) after the beginning of the reception of the operation code C0, the operated equipment 18 determines that the same operation key is being continuously operated. If, on the other hand, the operated equipment has not received the next code within the time period T0+α, the operated equipment 18 normally determines that the key operation has been terminated. Thus, in a case where T1>T0+α, even if continuous depressing operation has been performed by the user on the infrared remote control transmitter 12, the infrared remote control re-transmitter 16 can not transmit an infrared remote control signal 22 of the next code within the time period T0+α following the transmission of the infrared remote control signal 22 of the leading operation code C0. As a result, the operated equipment 18 can not detect the continuous depressing operation, and thus, it can not perform a process corresponding to the continuous depressing operation.